I hate to sound like my grandfather when I was 12 but kids these days dint have the respect for things that were taught when I was young. My family had guns in the house, my father kept his hunting knives out, his lighter, and his razor. We were taught not to touch unless dad was there and only if we asked and he said yes. Him allowing us to look at and handle these things took away the allure of doing so when he was not around, as did the thought of the consequences, but his showing us always included a safety lesson. When I was 10 firing a shotgun into a pumpkin at 15 feet gave me a respect for guns no lecture could ever impart.

I am very sorry your razor was damaged and sorry your space invaded; but it sounds like you need to protect your things as the people around you dint have the same respect for them you do. A shame but reality. Even the solution, "his father is buying me a strop to pay for the damage".. What about him doing something for the money to make up for his lack of respect for your razor? Him washing your car 25 times or something might be a better lesson than a cut finger.